Correlates of coronary artery calcified plaque in blacks and whites with type 2 diabetes

To examine whether the relationship between cardiovascular disease risk factors and coronary artery calcification (CAC) is modified by race among those with diabetes.

Data were pooled data from three studies (Multi-Ethnic Study of Atherosclerosis, Family Heart Study, Diabetes Heart Study) for a total of 835 blacks and 1122 whites with diabetes. CAC was quantified by cardiac computed tomography and risk factors were obtained using standard methods. Regression models examined the relationship between risk factors and presence and quantity of CAC.

The average age of the cohort was 60 years; 57% were women. Presence of CAC was lower in blacks compared to whites (odds ratio = 0.22 for men, 0.57 for women, p <0.01). Hemoglobin A1c, duration of diabetes, low-density lipoprotein, smoking, and body mass index were independently associated with presence of CAC; high-density lipoprotein, triglycerides, and C-reactive protein were not. Race did not modify these associations. Adjustment for multiple risk factors did not explain the race disparity in CAC.

CAC was reduced in blacks compared to whites in persons with diabetes. This effect was most pronounced in men. The relationship between risk factors and CAC did not differ between races. Racial differences in CAC are likely due to unmeasured risk factors and/or genetic susceptibility.